It depends IF you have a 'Ballast coil', which should be marked on it. If you don't there isn't a problem, providing that has a 12V supply.

If you do, then yes to keep the current coil you need to add a resistor, I don't know the value offhand but from my GCSE electronics, I remember there is a calculation you can do.

The feed needs to be taken from the starter.

Martin